## DNA Timeline

Explore the history of DNA on this interactive timeline. Discover key moments in the study of DNA as well as more recent developments in DNA technology, such as genetically engineered food and cloning.

## Drawing a Box Plot

Learn how to represent the Five-Number Summary graphically using a box plot.

## Dynamic Earth

Delve into the structure of the Earth to learn what causes earthquakes, volcanoes, and more.

## Dynamic Earth Assessment: Test Your Skills

Test your knowledge of the earth’s layers and the shifts that create mountains, volcanoes and earthquakes. Take this 30-question test, review your answers, and print out your assessment.

## Earth's Plates

Examine clues about the behavior, history and appearance of various volcanoes. Then try to locate the volcanoes on the map.

## Ecology Lab

Build your own ecosystem, and explore the effects of these interrelationships.

## Economic Timeline

The economic landscape has drastically changed throughout history. Use this timeline to dig deeper, discover relationships, and explore concepts.

## Elections and Issues

You've just found out that your neighborhood has been declared a gun-free zone. Choose which side of the issue you are on, and decide which civic actions you will take to support your position.

## Energy Lab

Try to meet the world's projected energy demand by choosing from the available energy sources, while keeping atmospheric CO2 under control. You must avoid the limits and pitfalls associated with each energy source.

## Enveloping Functions

Investigate the characteristics of functions. How do graphs of functions change when coefficients are changed?

## Equivalent Expressions

Determine if nine mathematical expressions are equivalent to 20. Then match the equivalent expressions to corresponding word problems.

## Eric the Sheep

One way to solve a complicated problem is to solve a smaller version of the same problem. Without working out the larger problem, predict how many sheep will get shorn before impatient Eric, who is sneaking up in line little by little.

## Espana

Practice some of the vocabulary and grammar covered in the Espana episodes of Destinos.

## European Colonies Challenge

See how much you know about the European powers and the colonies they established in North America. Then boost your score in the lightning round as you locate the original 13 states.

## European Union Timeline

Since the end of World War II, many European countries have been working to foster increasing unity. This interactive timeline traces the development and future of the European Union.

## Evaluating Web Sites

Practice evaluating Web sites to determine which ones are the most useful. Browse a Web site and evaluate it by answering the basic questions of who, what, when, where, why and how.

## Even Data Sets

How do you find the median for an even numbers of noodles? Learn how in this three-noodle summary of twelve noodles.

## Evolution of Large Scale Structure in the Universe

Vary two of the most important cosmological parameters, run the simulation and try to build our universe. Compare your simulated universe to real observations.

## Evolution of Túngara Frog Mating Calls

Use molecular information and observe female response patterns to learn about the mating calls of Physalaemus frogs. Examine the evolution of female preference for particular call characteristics. View non-Flash version.